Article
Chemistry, Physical
Vishakha Kaushik, Hardik L. Kagdada, Dheeraj K. Singh, Sachin Pathak
Summary: The study explores hybrid SERS substrates prepared by coating silver nanoparticles on graphene layers, utilizing both chemical and electromagnetic enhancement mechanisms for remarkable SERS intensities. The experiment and theory demonstrate substantial enhancement in electronic and vibrational properties of graphene fragments through interactions with small silver clusters, leading to enhanced G-band intensity. This research contributes to the understanding of mechanisms and the development of high-performance SERS substrates for sensing applications.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Meenu Sharma, Sonam Rani, Devesh K. Pathak, Ravi Bhatia, Rajesh Kumar, I Sameera
Summary: The temperature dependent Raman spectroscopy of reduced graphene oxide (rGO) reveals the combined effect of anharmonicity, crystallite size, and defects on the peak positions and line widths of G- and D- modes. The dominance of true-anharmonic part in shifting the peak positions is indicated by theoretical models. The contributions of electron-phonon coupling, anharmonicity, and defects to the temperature dependent variation of line width are discussed.
Article
Chemistry, Multidisciplinary
Kishan Thodkar, Milivoj Plodinec, Fabian Gramm, Karsten Kunze
Summary: Quantifying the intrinsic properties of 2D materials is crucial for their applications. This study demonstrates a method for preparing suspended chemical vapor deposition (CVD) graphene films directly on their growth substrates, allowing for the quantification of intrinsic strain and doping. The results show consistent patterns of compressive strain in the films and highlight the importance of studying materials directly on their growth substrates to avoid transfer-induced alterations.
Article
Chemistry, Physical
Alice Apponi, Domenica Convertino, Neeraj Mishra, Camilla Coletti, Mauro Iodice, Franco Frasconi, Federico Pilo, Narcis Silviu Blaj, Daniele Paoloni, Ilaria Rago, Giovanni De Bellis, Gianluca Cavoto, Alessandro Ruocco
Summary: In this study, accurate transmission measurements of electrons below 1 keV through suspended monolayer graphene were reported. The monolayer graphene was grown using chemical vapor deposition and transferred onto transmission electron microscopy (TEM) grids. The transparency of graphene was obtained by measuring the direct beam current and transmitted current. The experimental results showed a transmission rate ranging from about 20% to about 80% for monolayer graphene within the experimental electron energy range. The high quality and grid coverage of the suspended graphene were confirmed through various characterization techniques. Additionally, evidence of suspended monolayer graphene was observed after annealing the samples in vacuum at 550 degrees C.
Article
Nanoscience & Nanotechnology
Mahmound Tamadoni Saray, Vitaliy Yurkiv, Reza Shahbazian-Yassar
Summary: Ultrafast heating accelerates the synthesis processes and controls the morphology of nanoparticles. This study investigates the formation of nickel nanoparticles on graphene oxide substrates under slow and ultrafast heating rates. The results show that the structure of graphene oxide plays a crucial role in stabilizing hexagonally close-packed nickel nanoparticles during ultrafast heating. In contrast, face-centered cubic nickel nanoparticles are formed under slow heating without a strong correlation with the substrate structure. Additionally, ultrafast heating leads to smaller-size nanoparticles due to rapid reduction, nucleation rate, and higher diffusion barrier. However, the crystal structure stability of nickel nanoparticles is unaffected by their size. These findings highlight the importance of the substrate in controlling the crystal structure during nonequilibrium processing and the competing effects of thermodynamics and kinetics in creating novel phases for energy storage and conversion applications.
ACS APPLIED NANO MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Kenan Elibol, Peter A. Van Aken
Summary: Controlled fabrication of devices for plasmonics on suspended graphene enables tunable localized surface plasmon resonances and the creation of hybrid 3D-2D systems, which have potential applications in adjustable dipole-dipole coupling and plasmon-mediated catalysis.
Article
Chemistry, Physical
D. Manno, L. Torrisi, L. Silipigni, A. Buccolieri, M. Cutroneo, A. Torrisi, L. Calcagnile, A. Serra
Summary: Ion irradiation reduces oxidized graphene and causes morphological and structural changes in the individual sheets. The study analyzes the changes in reduced graphene oxide (rGO) through transmission electron microscopy and Raman spectroscopy. The analysis reveals deformations in the sheets and the presence of different orientations within the electron beam. The results suggest that ion dose affects the deformation and morphology of the sheets.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Ceramics
Kelvin Y. Xie, Qirong Yang, Christopher J. Marvel, Mo-Rigen He, Jerry C. LaSalvia, Martin P. Harmer, Chawon Hwang, Richard A. Haber, Kevin J. Hemker
Summary: This paper reviews the progressive understanding of amorphization in three successive generations of boron carbide, comparing the susceptibility of amorphization in each generation and elucidating the fundamental mechanisms that explain the reduction in amorphization for B-rich and B/Si codoped boron carbides. Future research directions to further deepen the understanding of stress-induced amorphization of boron carbide are also discussed.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Chemistry, Physical
M. Pelaez-Fernandez, A. Bermejo, A. M. Benito, W. K. Maser, R. Arenal
Summary: An in-depth study of reducing graphene oxide by in-situ thermal TEM analysis was conducted, with focus on the transformations of oxygen functional groups, water desorption, and graphitisation as a function of temperature. A model for water and oxygen functional groups removal was proposed based on monitored chemical and physical parameters. The unique information provides a detailed roadmap of GO's thermal behavior at an extended temperature range, which is important for understanding its response to thermal effects in applications.
Article
Chemistry, Multidisciplinary
Jatin J. Patil, Zhengmao Lu, Michael J. Zachman, Ningxin Chen, Kimberly S. Reeves, Asmita Jana, Griselda Revia, Brandon MacDonald, Brent D. Keller, Edgar Lara-Curzio, Jeffrey C. Grossman, Nicola Ferralis
Summary: Graphene oxide (GO) is a promising membrane material that can be used for chemical separations, including water treatment. However, often chemical modifications are needed to improve the permeability, performance, or mechanical integrity of GO membranes. In this study, we explore two different feedstocks of GO and observe significant improvements in permeability and chemical stability. These findings are connected to differences in sheet stacking and oxide functional groups through various characterization approaches.
Article
Engineering, Electrical & Electronic
Ritesh Kumar Singh, Pavar Sai Kumar, Khairunnisa Amreen, Satish Kumar Dubey, Sanket Goel
Summary: A paper-based miniaturized sensor with reduced graphene oxide has been developed for temperature, breath, blow, and touch sensing. The sensor exhibits good sensitivity and accuracy. Whatman filter paper was used as a substrate for laser ablation to form rGO as an interdigitated electrode, which was then characterized using various techniques. The sensor shows a sensitivity of 1.46% degrees C-1, linearity (R-2 = 0.993), and a resolution of 1 degrees C within the temperature range of 25 degrees C-60 degrees C, demonstrating a negative temperature coefficient (NTC) of 0.0016 degrees C-1. Furthermore, the sensor has been applied for breath, blow, and touch sensing.
IEEE SENSORS JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Yasir Sohail, Arslan Liaquat, A. ul Haq, M. Farooq Zafar, Noaman Ul-Haq
Summary: CuFe2O4 was synthesized by the co-precipitation method, and RGO/CuFe2O4 nanocomposites were prepared using the hydrothermal method. The results showed that the reduction in RGO concentration in the composites led to a decrease in the average grain size, while the copper ferrite was well distributed and firmly anchored on the RGO surface. Additionally, in terms of dielectric properties and AC conductivity, composites with certain RGO contents exhibited good performance.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Chemistry, Analytical
Muhammad Ans
Summary: The study found that using a coating method with graphene oxide can significantly improve the oxidation stability of copper. In the short term, a monolayer of graphene oxide does not significantly affect the oxidation kinetics; however, in the long term, the graphene oxide film can effectively reduce the further propagation of the cuprous oxide layer.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Physical
Revathi Kottappara, Shajesh Palantavida, Suresh C. Pillai, Baiju Kizhakkekilikoodayil Vijayan
Summary: A direct low-cost chemical reduction method is presented for the synthesis of the ternary Cu-Cu2O-CuO system, where the presence of graphene oxide helps limit the conversion of copper to copper oxide. The composition of the ternary system can be altered by adjusting the amount of copper precursor used, as confirmed by X-ray diffraction studies and XPS analysis of the synthesized nanocomposites. The enhanced catalytic efficiency of the composite nanostructures towards visible light photodegradation and hydride reduction reactions is attributed to the interaction between graphene sheets and copper, as well as the unique ternary composition of Cu2O-Cu-CuO.
SURFACES AND INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Ramy Sadek, Mohammad S. Sharawi, Charles Dubois, Hesham Tantawy, Jamal Chaouki
Summary: The study presents a cost-effective and scalable method for industrial production of Reduced Graphene Oxide (RGO) by combining chemical reduction and thermal treatment. The RGO produced has high electromagnetic interference (EMI) shielding performance, surpassing other graphene reduction mechanisms.
